Fuel supply systems for fourstroke internal combustion engines

ABSTRACT

The system enables the supply of fuel to a four-stroke internal combustion engine comprising two pairs of cylinders in each pair of which the cycles of the two cylinders are separated by 360* of rotation of the engine shaft. It includes four injection valves actuated by electromagnets controlled by an actuating device driven by a shaft at half the speed of the engine shaft. It is arranged so that each cylinder of each pair receives on each cycle two doses of fuel for periods of equal duration separated by 360* of rotation of the engine shaft.

United States Patent 91 Mennesson 1 1 FUEL SUPPLY SYSTEMS FOR F OURSTROKE INTERNAL COMBUSTION ENGINES [75] Inventor: Andre Louis Mennesson, 92 Neuilly sur Seine, France [73] Assignee: Societe Industrielle de Brevets et DEt'udes S.I.B.E., Neuilly-surSeine,

France [22] Filed: July 28, 1970 [21] App]. No.: 58,852

[ Apr. 17, 1973 3,216,407 11/1965 Eyzat ..123/32 3,548,791 12/1970 Long ....l23/32 EA 3,054,393 10/1962 Schmidt... ..123/32 G 2,974,657 3/1961 Bessiere ..123/32 G 3,014,466 12/1961 Morinot et a1.. 1 23/32 G 3,439,655 4/1969 Eyzat ..l23/32 G 3,430,616 3/1969 G10ck1er.. ....123 /32 EA 3,460,520 8/1969 Huber .l .123/32 EA 3,543,739 12/1970 Mennesson .......123/32 EA Primary Examiner-Laurence M. Goodridge Assistant Examiner-Cort Flint Atl0rneyFleit, Gipple & Jacobson [57] ABSTRACT The system enables the supply of fuel to a four-stroke internal combustion engine comprising two pairs of cylinders in each pair of which the cycles of the two cylinders are separated by 360 of rotation of the engine shaft. It includes four injection valves actuated by electromagnets controlled by an actuating device driven by a shaft at half the speed of the engine shaft. It is arranged so that each cylinder of each pair receives on each cycle two doses of fuel for periods of equal duration separated by 360 of rotation of the engine shaft.

2 Claims, 4 Drawing Figures PATENTEUAPR 1 11915 a; 727. 590

sum a nr 3 The invention relates to fuel supply systems for fourstroke internal combustion engines of the type comprising at least one pair of combustion chambers whose respective cycles of operation are displaced by 360 of rotation of the engine shaft, these combustion chambers being of the cylinder-piston type or of any other variable volume chamber type.

And it relates more particularly, since it is in this case that its application seems to have most advantage; but not exclusively, among these fuel supply systems. to those comprising,

a main air intake pipe supplying individual air intake pipes connected respectively to each combustion chamber of the engine, the abovesaid main intake pipe being equipped with main throttle member actuated by the operator and an auxiliary throttle member, situated upstream of this main throttle member, opening automatically and progressively in proportion as the flow of air in themain intake pipe increases,

means for injecting liquid fuel under pressure into each of the abovesaid individual intake pipes connected respectively to each of the combustion chambers of the, engine, these means being generally constituted by a common source of fuel under pressure serving injection valves (one per individual intake pipe) each actuated by an electro-magnet and phase-locked, as regards the energizing of their electro-magnets, to a control-apparatus moved by a rotary member driven in continuous rotation by the engine,

and, lastly a fuel metering system sensitive to the position of the auxiliary throttle member and adapted to adjust the total flow of fuel injected per cycle of operation of the engine in such a way that the richness of the air fuel mixture formed in the individual intake pipes is substantially constant, at least for certain conditions of operation of the engine.

Supply systems of this particular type are known and are the subject, especially, of U.S.,Pat. No. 3,543,739 filed Oct. 9, 1968 by applicant. I I

It has already been proposed, where the supply of a multi-cylinder engine with such system is concerned,

either to have recourse to a pulse distributor directing successively towards the electromagnets of the various injection valves the pulses generated by a common energy flow emittor, this solution being relatively burdensome and sometimes subject to operational problems,

or to send simultaneously into at least two of the abovesaid electromagnets, once per cycle of the engine, pulses generated by a common energy flow emittor, this solution enabling a distributor to be dispensed with but having the drawback of creating a dissymetry in the injection program due to the fact that the various cylinders supplied simultaneously, once per cycle, receive their dose of fuel at different times of their respective cycles.

It is a particular object of the invention, in the case of a four stroke internal combustion engine with at least one pair of combustion chambers whose respective cy cles of operation are out of phase by 360, to overcome the above-mentioned drawbacks of the previous solutions regarding the supply of fuel to the several cylinders or combustion chambers.

The following expressions are used in this description and claims:

An engine cycle is the time required for all the combustion chambers to complete one respective cycle of operation and corresponds to two complete revolutions of the the engine shaft (720).

A dose is the full charge of fuel required for the firing of one combustion chamber during one cycle of operation of the chamber, a half-dose being one half of the full charge.

The fuel supply system according to the invention, intended for the supply of a four stroke internal combustion engine comprising at least one pair of combustion chambers whose respective cycles of operation are phase-shifted by 360, comprises, individual intake pipes associated respectively with each combustion chamber, obturator means with intermittent action provided for each individual intake pipe and enabling, when they are actuated, the introduction of fuel under pressure into the corresponding individual air intake pipe, and lastly, a control device adapted to ensure cyclic actuation of the abovesaid obturator means in synchronism with the rotation of the engine shaft, the

' abovesaid fuel supply system being characterized by the fact that the abovesaid control device is arranged so that the obturator means with intermittent action associated respectively with each of the combustion chambers of the pair of the combustion chambers concerned are actuated simultaneously, on each cycle of the engine, during two periods of equal duration displaced by 360 in the said cycle, so that the supply of fuel to the individual intake pipe of each combustion chamber is provided at the rate of two half-doses per cycle equal and displaced by 360.

It will be understood that such :a supply system ensures finally complete symmetry in the supply of the two combustion chambers with respective cycles of operation phase-shifted by 360.

lf fact, on the simultaneous introduction of the two half-doses respectively into the two combustion chambers, the latter have, by definition, a phase difference of 360. According to the invention, the simultaneous introduction of two other half-doses will intervene with a phase shift of 360, ie at a period when, on the one hand, the first combustion chamber is in the phase that the second combustion chamber was in on the introduction of the previous two half-doses, and, on the other hand, the second combustion chamber is in the phase that the first combustion chamber was in on the introduction of the previous two half-doses.

In other words, once a complete cycle of the engine has been effected, the two combustion chambers will have finally received each two half-doses of fuel at the same times in their cycle, which does constitute a complete symmetry of their supply.

When the engine comprises n pairs of combustion chambers operating at cycles displaced by 360, each pair of combustion chambers has to be supplied, as has just been stated,

either by n distinct single control devices each serving one pair of combustion chambers,

or, and better, by a single complex control device comprising n distinct active members displaced angularly by l80/n, assuming that this control device is a rotary device which has to ensure in one revolution thereof the supply of the engine with fuel during one cycle.

There will now be described, with reference to the accompanying drawings, a preferred embodiment of the invention, this embodiment being purely illustrative and in no way limiting.

FIG. 1 of these drawings, shows, in very diagrammatic manner, a four cylinder internal combustion engine supplied with fuel by a system according to the invention.

FIG. 2 is a diagram illustrating the operation of the supply system shown in diagrammatic manner in FIG. 1.

FIGS. 3 and 4, lastly, show, respectively, in elevation and in transverse section along the broken line IVIV of FIG. 3, a particular embodiment of the control system of the abovesaid supply device.

There is shown diagrammatically, in FIG. 1, a type of four stroke internal combustion engine for which a fuel supply system according to the invention is particularly advantageous by reason of the total symmetry which it permits during the process of supply, which symmetry is manifested by a greater regularity of speed and by less fatigue in the moving parts of the engine.

This engine comprises four cylinders, or more precisely two pairs of cylinders la and 1b, on one hand, and 2a and 2b, on the other hand, the two cylinders ofa same pair having respective operating cycles displaced by 360 and the two pairs of cylinders being displaced with respect to one another by half. a revolution of the crankshaft.

The period of the combined operating cycles of the two pairs of chambers corresponds to two revolutions of the engine shaft.

The configuration shown in FIG. 1 corresponds to the case where the cylinder 1a is at the start of its intake stroke and the cylinder 1b is at the start of its expansion stroke, while the cylinder 2a is at the beginning of its compression stroke and the cylinder 2b at the beginning ofits exhaust stroke.

Now as regards the supply system for fuel under pressure intended to equip this engine, it is constructed so that it is of a type for the controlled injection of fuel into the individual air intake pipes of these cylinders.

To this end, there can advantageously and in manner known in itself, be included in the said supply system, as illustrated diagrammatically in FlG. l,

a main air intake pipe 3 feeding with air individual intake pipes 4 associated respectively with each of the cylinders la, Ih, 20, 2b, the abovesaid main intake pipe 3 being equipped with a main throttle member 5, such as a butterfly valve, actuated by the operator, and an auxiliary throttle member 6, advantageously also ofthe butterfly valve type, situated upstream of the main throttle member 5 and governed by control means 7 (which will be more explicitly described below) causing progressive opening of the said auxiliary throttle member when the flow of air in the abovesaid main intake pipe increases,

means for injecting under pressure liquid fuel into each of the individual air intake pipes 4, these means beingable to be constituted by connecting a source of liquid fuel under pressure (not shown) to four obturator means, such as injection valves 101a, 101b, 102a, 102b opening respectively inside the four individual pipes 4 serving the cylinders la, 1b, 2a and 2b with air, the abovesaid valves being actuated respectively by eleetromagnets 201a, 201b, 202a and 20217 causing the opening of the corresponding injection valve when they are energized,

a control apparatus 8 adapted to ensure the energizing of the abovesaid electromagnets according to a predetermined law which will be considered below with regard to the main feature 'of the invention, the abovesaid control apparatus 8 being moved by a rotary shaft 9 driven in continuous rotation by the engine at half the speed of said engine.

This being so and according to the abovesaid main feature, profiting from the fact that the four stroke engine concerned includes two pairs of cylinders (pair 1a, lb, on one hand, and pair 2a, 212, on the other hand) in each pair of which the two cylinders constituting the pair concerned have respective cycles of operation displaced by 360, the control apparatus 8 is arranged in such a way that,

for the pair of cylinders 1a, 1b, the electromagnets 201a,-20lb are energized simultaneously, on each cycle of the engine, for two periods of equal duration F a and P 1; displaced by 360 in the cycle of this pair of cylinders,

and, for the pair of cylinders 2a, 2b, the electromagnets 202a, 2025 are energized simultaneously, on each cycle of the engine, for two periods of equal duration P a and P b coinciding with Pa and Pb respectively and displaced also by 360 in the cycle of this pair of cylinders.

There is shown, in the diagram of FIG. 2, by two concentric circles, the two crankshaft revolutions of a four stroke cycle, with indication of the top dead center PMH and the bottom dead center PMB, the periods of injection P'a, Pb, P a and Pb being marked in heavy lines.

It is seen that these periods have the same duration and take effect over the same angular fraction V of the crankshaft revolutions.

This diagram of FIG. 2 illustrates in eloquent manner the total symmetry of the injection system according to the invention.

Now as regards the actual construction of the rotary control apparatus 8 which has to ensure the injection sequence according to the main feature of the invention, it can advantageously have recourse, for its production, to features which formed the subject of the patent mentioned previously and, especially, have recourse to the embodiment illustrated in the FIGS. 3 and 4 and according to which procedure is as follows Taking into account the fact, mentioned in the abovesaid patent, that the degree of opening imposed on the auxiliary butterfly valve 6 by the control means 7 which will be more explicitly considered below, is approximately proportional to the flow of air passing through the air intake pipe 3, there ismade to bear, through the axle 10 of the auxiliary butterfly valve 6, a U-shaped part 11 of which one of the wings bears an energy flow emittor advantageously constituted by an electric lamp 12 and of which the other wing bears, facing the said lamp, a detector of this energy flow, which detector is constituted in this instance by a photo diode l3.

Adjacent the cross-member joining the two wings of the U-shaped part 11, is positioned part of a rotary disk 14 rotated by an axle l5 driven by the engine at a speed half of that of the engine shaft, the abovesaid disk 14 having a first aperture 16 whose position is such that, on each revolution of the disk, it passes once between the lamp 12 and the photo diode 13 thereby giving rise to an energization of the said photo diode which then emits a signal whose duration corresponds to the duration of passage of the aperture 16 between the abovesaid lamp and the abovesaid photo diode.

An electronic amplifying circuit 17, for example a conventional transistor circuit such as that shown in FIG. 4, transmits, after transformation, the signals emitted by the photo diode 13 to the electromagnets 201a and 20lb controlling the injection valves 101a and 101b associated with the pair of cylinders la, lb with respective cycles displaced by 360.

With a view to ensuring the control of the electromagnets 202a and 202b relative to the injection valves 102a and 1021) associated with the second pair of cylinders 2a, 2b with respective cycles displaced by 360, there is provided a second control system, similar to the previous one, comprising a second U-shaped part 18 (visible in FIG. 3) hinged on a fixed axle 19 parallel to the axle of the auxiliary butterfly valve 6 and having the same eccentricity as this axle 10 relative to the axle of the disc 14, being however displaced angularly by 90 with respect to the said axle 10 (displacement observed from the axle 15), the abovesaid U- shaped part 18 being coupled tothe U-shaped part 11 by an incurved connecting rod 20 imposing on the U- shaped part 18, around its axle l9, angular displacements identical with those undergone by the abovesaid U-shaped part 11.

The wings of the U-shaped part 18 bear, as in the case of the U-shaped part 11, an electric lamp 21 coacting with a photo diode. An electronic control circuit similar to the circuit 17 (which photo diode and circuit have not been shown for reasons of clarity in the drawing) serves for the control of the electromagnets 202a and 202b associated with the second pair of cylinders 2a, 2b having respective cycles displaced by 360.

To obtain the double injection per cycle desired for each cylinder, there is provided a second aperture 22 (identical with the aperture 16 but displaced by l80 with respect to the latter).

Finally, as regards the control means 7 of the angular position of the auxiliary butterfly valve 6, these are advantageously constituted, as shown in FIG. 4.

The axle 10 of the said auxiliary butterfly valve, is coupled through a crank 23, to a rod 24 fixed to the center of a diaphragm 25, a return spring 26 urging this assembly towards the closed position of the abovesaid auxiliary butterfly valve.

The volume 28, comprised between a casing 29 and the outer surface of the diaphragm 25, is made to communicate through a passage partially shown at 27 in FIG. 3, with the space of the pipe 3 comprised between the butterfly valves 5 and 6.

In this way, the diaphragm imposes on the auxiliary butterfly valve 6, against the counteraction of the spring 26, a degree of opening which is a function increases with the flow of air in the pipe 1.

Such a control apparatus for the injection periods operates according to a cycle which is effectively that explained by the diagram of FIG. 2 regarding the main feature of the invention.

As is self-evident and as emerges already besides from the preceding description, the invention is in no way limited to those of its methods of application, nor to those of its methods of production of its various parts, which have been more particularly considered.

I claim:

1. Fuel supply system for a four-stroke internal combustion engine, having an engine shaft which revolves twice in each engine cycle, at least one pair of com,- bustion chambers, whose respective operating cycles are separated by 360 of revolution of the engine shaft, said device comprising individual air intake pipes connected to each respective combustion chamber, each chamber having a valved inlet connected to an individual intake pipe and a valved outlet, a source of fuel under pressure, obturator means with intermittent action provided at each individual air intake pipe and arranged to enable when they are actuated, the introduction of said fuel into the corresponding individual air intake pipe, and a control device adapted to ensure cyclic actuation of said obturator means phase-coupled to the rotation of the engine shaft, said control device being arranged so that the obturator means for each combustion chamberof said pair of combustion chambers are actuated simultaneously, in each said engine cycle, during two equal periods displaced by 360 in said engine cycle, so that each combustion chamber of each pair is supplied. with fuel in two half-doses per respective operating cycle, wherein the obturator means comprise injection valves actuated by electromagnets, an electronic device governing said electromagnets and actuated by a rotary member comprising emitter/detector means adapted to emit, towards a nonrotary receiver, a flux of energy during a fraction of a revolution of said rotary member whose value varies as a function of the relative position of said rotary member and of said receiver,

wherein said receiver is responsive to the energy flux and has two states, namely a state corresponding to reception of flux and a state corresponding to nonreception of flux, and said receiver is arranged to control the energization circuit of said electromagnet according to the state of said receiver, and auxiliary throttle means for modifying the relative position of said rotary member and of said receiver as a function of the air flow rate in the air intake pipe of the engine, said emitter/detector intervening during two periods of equal duration separated by 360 for each operating cycle of the respective chamber.

2. Fuel supply system for a four-stroke internal combustion engine, having an engine shaft which revolves twice in each engine cycle, at least one pair of combustion chambers, whose respective operating cycles are separated by 360 of revolution of the engine shaft, said device comprising individual air intake pipes connected to each respective combustion chamber, each chamber having a valved inlet connected to an individual intake pipe and a' valved outlet, a source of fuel under pressure, obturator means with intermittent action provided at each individual air intake pipe and arranged to enable, when they are actuated, the introduction of said fuel into the corresponding individual air intake pipe, and a control device adapted to ensure cyclic actuation of said obturator means phase-coupled to the rotation of the engine shaft, said control device being arranged so that the obturator means for each combustion chamber of said pair of combustion chambers are actuated simultaneously, in each said engine cycle, during two equal periods displaced by 360 in said engine cycle, so that each combustion chamber of each pair is supplied with fuel in two half-doses per respective operating cycle, wherein said engine has n said pairs of combustion chambers and said control device comprises rotary means common to said n pairs of combustion chambers and including n distinct actuating members angularly separated by l80/n, said rotary means being arranged so as to ensure in one revolution of said rotary means the supply of the engine with fuel during one said engine cycle, and wherein the obturator means comprise injection valves actuated by electromagnets, an electronic device governing said electromagnets and actuated by a rotary member comprising emitter/detector means adapted to emit, towards a nonrotary receiver, a flux of energy during a fraction of a revolution of said rotary member whose value varies as a function of the relative position of said rotary member and of said receiver,

wherein said receiver is responsive to the energy flux and has two states, namely a state corresponding to reception of flux and a state corresponding to nonreception of flux, and said receiver is arranged to control the energization circuit of said electromagnet according to the state of said receiver, and auxiliary throttle means for modifying the relative position of said rotary member and of said receiver as a function of the air flow rate in the air intake pipe of the engine, said emitter/detector intervening during two periods of equal duration separated by 360 for each operating cycle of the respective chamber. 

1. Fuel supply system for a four-stroke internal combustion engine, having an engine shaft which revolves twice in each engine cycle, at least one pair of combustion chambers, whose respective operating cycles are separated by 360* of revolution of the engine shaft, said device comprising individual air intake pipes connected to each respective combustion chamber, each chamber having a valved inlet connected to an individual intake pipe and a valved outlet, a source of fuel under pressure, obturator means with intermittent action provided at each individual air intake pipe and arranged to enable when they are actuated, the introduction of said fuel into the corresponding individual air intake pipe, and a control device adapted to ensure cyclic actuation of said obturator means phase-coupled to the rotation of the engine shaft, said control device being arranged so that the obturator means for each combustion chamber of said pair of combustion chambers are actuated simultaneously, in each said engine cycle, during two equal periods displaced by 360* in said engine cycle, so that each combustion chamber of each pair is supplied with fuel in two half-doses per respective operating cycle, wherein the obturator means comprIse injection valves actuated by electromagnets, an electronic device governing said electromagnets and actuated by a rotary member comprising emitter/detector means adapted to emit, towards a nonrotary receiver, a flux of energy during a fraction of a revolution of said rotary member whose value varies as a function of the relative position of said rotary member and of said receiver, wherein said receiver is responsive to the energy flux and has two states, namely a state corresponding to reception of flux and a state corresponding to nonreception of flux, and said receiver is arranged to control the energization circuit of said electromagnet according to the state of said receiver, and auxiliary throttle means for modifying the relative position of said rotary member and of said receiver as a function of the air flow rate in the air intake pipe of the engine, said emitter/detector intervening during two periods of equal duration separated by 360* for each operating cycle of the respective chamber.
 2. Fuel supply system for a four-stroke internal combustion engine, having an engine shaft which revolves twice in each engine cycle, at least one pair of combustion chambers, whose respective operating cycles are separated by 360* of revolution of the engine shaft, said device comprising individual air intake pipes connected to each respective combustion chamber, each chamber having a valved inlet connected to an individual intake pipe and a valved outlet, a source of fuel under pressure, obturator means with intermittent action provided at each individual air intake pipe and arranged to enable, when they are actuated, the introduction of said fuel into the corresponding individual air intake pipe, and a control device adapted to ensure cyclic actuation of said obturator means phase-coupled to the rotation of the engine shaft, said control device being arranged so that the obturator means for each combustion chamber of said pair of combustion chambers are actuated simultaneously, in each said engine cycle, during two equal periods displaced by 360* in said engine cycle, so that each combustion chamber of each pair is supplied with fuel in two half-doses per respective operating cycle, wherein said engine has n said pairs of combustion chambers and said control device comprises rotary means common to said n pairs of combustion chambers and including n distinct actuating members angularly separated by 180* /n, said rotary means being arranged so as to ensure in one revolution of said rotary means the supply of the engine with fuel during one said engine cycle, and wherein the obturator means comprise injection valves actuated by electromagnets, an electronic device governing said electromagnets and actuated by a rotary member comprising emitter/detector means adapted to emit, towards a nonrotary receiver, a flux of energy during a fraction of a revolution of said rotary member whose value varies as a function of the relative position of said rotary member and of said receiver, wherein said receiver is responsive to the energy flux and has two states, namely a state corresponding to reception of flux and a state corresponding to nonreception of flux, and said receiver is arranged to control the energization circuit of said electromagnet according to the state of said receiver, and auxiliary throttle means for modifying the relative position of said rotary member and of said receiver as a function of the air flow rate in the air intake pipe of the engine, said emitter/detector intervening during two periods of equal duration separated by 360* for each operating cycle of the respective chamber. 